Predictability of Decadal Atlantic Meridional Overturning Circulation Variations

• Main Authors: Sévellec, Florian, Sinha, Bablu
• Other Authors: Ocean and Earth Science Southampton, University of Southampton-National Oceanography Centre (NOC), National Oceanography Centre (NOC)
• Format: Book Part
• Language: English
• Published: HAL CCSD 2018
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; North Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-02136510; https://hal.archives-ouvertes.fr/hal-02136510/document; https://hal.archives-ouvertes.fr/hal-02136510/file/sevellec_and_sinha-ORE-CS18.pdf; https://doi.org/10.1093/acrefore/9780190228620.013.81

International audience and Keywords The Atlantic meridional overturning circulation (AMOC) is a large, basin-scale circulation located in the Atlantic Ocean that transports climatically important quantities of heat northward. It can be described schematically as a northward flow in the warm upper ocean and a southward return flow at depth in much colder water. The heat capacity of a layer of 2 m of seawater is equivalent to that of the entire atmosphere; therefore, ocean heat content dominates Earth's energy storage. For this reason and because of the AMOC's typically slow decadal variations, the AMOC regulates North Atlantic climate and contributes to the relatively mild climate of Europe. Hence, predicting AMOC variations is crucial for predicting climate variations in regions bordering the North Atlantic. Similar to weather predictions, climate predictions are based on numerical simulations of the climate system. However, providing accurate predictions on such long timescales is far from straightforward. Even in a perfect model approach, where biases between numerical models and reality are ignored, the chaotic nature of AMOC variability (i.e., high sensitivity to initial conditions) is a significant source of uncertainty, limiting its accurate prediction.